Telegraphic repeating apparatus.



W. E. ATHEARN.

TELEGRAPHIG REPEATING APPARATUS.

APPLICATION FILED APR.29.1908.

I22 rezzzor Patented Dec. 1

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UNITED STATES PATENT OFFICE;

WILLIAM E ATHEhRhi, OF NEW YORK, Y.,. ASSIGNOR o AMERICAN TELEPHONE AND; v

' TELEGRAPH COMPANY, ATCORPORATION or NEW YORK.

' mmeltarmc REPEATING APPARATUS.

To. all whom it may concern: 4

3e i t known that I, WILLIAM E. Arenas N, residing at New York, borough of Brooklyn,"

- in the countyof Kings and .State ofNew them into'the other. This Invention, though obviously of more general application, 1s hereinafter described York, have invented certain Improvements in Telegraphic Repeating Apparatus, of which the following is aspecificatmn. f

- The present invention hasfreference to telegraph systems in which a multiplex cir-. cult, or one wherea plurality of messages may be transmitted slmultaneously over a single line, is employed to connect a circuit adapted for the transmission of one message at a time with another circuit? of the same character. The multiplex'line under such circumstances operates at anyinstant in one direction only, it receiving impulses from one single-transmission line and repeating as especially useful in connectionwith organizations in which this intermediate or repeating circuit is a polar bridge duplex constitut, ing one side, of a composite telephone and aph system.

teleglr I g V M h '1 e invention anus to secure this repeat ing action in a simple and effective manner, with a minimum number .of re etltlons of 'each impulse and with the addition of but fewmoving partsto the ordinary duplex apparatus. Y

A further object offthis invention: is to render the repeating system independent of a condition-of unbalance between the real and artificial lines, to which a composite cir circuit is peculiarly liable, on account of the wide variationsin the grounded capacity of the real line. U j V With these and-other objects in view, the

' invention consists in the-features and com} binations which will now beparticularly dewhich is one limb of a composite circuit, the

other side of whichris furnished by a conductor L At these stations, and others to be hereinafter mentioned, correspondingaparatus, with their elements and thoseof t e ocal circuits, will be designated b the same numerals at both the home and tant sta- Specification of Letters Patent. I

Application filed April 29, 1908. Serial No. 429,975.

Patented Dec. 1, 1908.

tions, but distinguished from one another by superscripts indicating the particular stathe telephone and tele raph currents are separated form no part 0 th1sinvention, and

maybe, for example, as describedlin the patent to William Athearn, No. 778,297, dated December 27, 1904. The conductor L would usually furnish means for communication between a second pair of telegraph stations, but as this side of the system would not difier essentially from that including the ,"conductor L, only the latter will be considered' The stations multiple telegraph lar duplex met od-,',this being-chosen ecause of its simplicity and because working by reversals of polarity gives, better results upon composite lines, whichusually have. a

high capacity, than does. operation by merely making ,and breaking the circuit. The apparatus for this purpose is shown as consisting ofkeys'. 10 and '10"; included in local circuits 11", 11 ,"ea-ch with a'battery or other source of current 12, 12 and the winding of a pole changing transmitter 13 and 13", respectively. These transmitters, by thefl'cooperation of their armatures or movable contact members 14 and 14? with front and back contacts 15*, 15 and1'6, 16 under the control of the associated home key, connect the opposite poles of main batteries 17 a and 17 to the line L. The resulting impulses are received ateach distant sta- .tionby polarizedlrelays 18 and 18 respectively, which are in bridges 19f, 19 from the A and B are arranged for ic'transmission by the oline L to corresponding artificialalines'20- 20 The relay armatures'21, 21" pla be tween front and back stops 22, 22 an 23,

23", contact with the former two of which applies current from batteries 24, and 24 to local circuits '25 and 25 including the winding of relays 26, 26 which open and close sounder circuits 27, 27. The construction of this a aratus and the arrangement of the artificial lines and accessory apparatus, except as hereinafter pointed out, is in accordance with standard ractice, and neither it nor the o eration oft e duplex system, as

such, need e further considered. Joined to the stations A and B by lines I:

iized, that the key at the sending substation overns the ole changing transmitter at its and Z respectively, are telegraph substations E and F adapted for single transmission. Keys 28", 28 and relays 29, 29' governing local circuits 30, 30 are situated at these substations, and serve to send andreceive Morse impulses in the usual manner by opening and closing the circuits of batteries 31 and 31 Switches 32, 32 33, 33 and 34, 34* are in. circuit at each of the stations A and B, and are associated, respectively,v

with the transmitters, polarized relays and substation lines. When these switches are thrown to the right they provide for the ordinary duplex operation of the system, exeluding the substations, but when at the left, as illustrated in the drawing, the duplex circuit will be prepared for the carrying out of this invention; and this aspect of the system will now be described in detail.

The apparatus and circuits are so organome contra station, which in turn operates the polarized relay at the distant central station, and this repeats directly'into the line of.

and actuate's the rela at the receiving substation. To accom ish this, the key and relay windin at eac substation is placed in series with't e' winding of the home transmitter and front stop and armature of the home polarized relay. Considering'E as the originating station, this transmitting por-' tion of the circuit will be from the grounded battery31 through the line I, including the Winding of relay 29, key 28 and switch 34,

' conductor 25?, including the winding of relay manipulated it will send pulses of current 26 and the front or normal resting contact 22 and armature-2'1 of the polarized'relay,

Switch 33 conductor 35, switch 32*? and conductor 11 in which is the winding of the transmitter 13, key 10, and battery-12 to ground. Therefore, when the key 28 is through the winding of the transmitter 13 at station A, causing the armature 14 to act as a secondary key. The alternatecontact of this armature with the stops 15 and 16' will send negative and positive currents from the groundedbattery 17% through the conductor 36 to ground, byway of both the real line L and the artificial line 20. When these lines are approximately balanced, or possess the same electrical properties, the otentials at the ends of the bridge. 19 will e equal for these outgoing currents, and the winding of the home polarized relay 18 will receive none of the transmitting current, so-

- the armature will be retained in its normal position against the frontv stop-22F by negative currentapplied by the distant. transmitter 13 as in duplex operation. Consequently,the transmitting circuit just traced ,remainsjmbroken. at the relay '18 and is under the full controlpof the key 28 The greater part of the outgoing current overathe switch 33*.

, tomes A line-L finds its wayto ground through the bridge 19" at the distant centralv station B,

including the Winding of olarized relay 18 and through theartiiicia line 20 The armature 21 of relay 18 is thus caused to atternately leave and engage its front. stop, 0 ening'and closing the receiving circuit, of

'w 1ich the substation line Z is a part, and repeating into this line the signals transmitted from the substation E, these beingreccived by the relay 29 at the substation 1*.

" It will be s'een'that although the non-op? eration of the home polarized relay has been provided for, .the transmitter 13" at the (listant central station, so far as-yet described, would-be actuated throughtthe interruption and completion of itscircuit by-the armature 21*. 'It thus becomes necessary to provide for the continuous energization of the transmitter during the operation of its associated relay. While the armature 21 is resting against its front stop 22 the winding of the transmitter 13 -will be traversed by the cur rent which operates'the receiving relay 29 I 7 When thearmature 21 is upon its back stop 23 ,a path to ground fromvbattery 12 is furnished through the Winding of the transmitter 13'" by 'a connection 36* and the This ground connection contains a resistance 37 approximating that of the circuit to ground through the line 1 and .it may therefore be considered as an artificial. line- Thus, the battery 12 'and the transmitter winding are in circuit 'withboth which, however, in a well known Way may;

be lessened by such a close adjustment of the contact stops of the said polar relay that the time required for the armature movement is very brief. It is, however,- found that the difficulty is not wholly met by thus shortening the travel ofthe armature, and that the exigencies of racticere uire that an energizing current s all be ava able and protracted through the pole changermagnet coils during the movement. period of the relay armature 21 This is'supplied by a condenser 38? contained in a ridge. 39 between the back stop 23 and conductor 35". -When the armature 21" leaves the front stop 22*, the battery 12*, severed from its ground connection through the line I increases the charge of this condenser, and the conse uent rush of current through the winding 0 the transmitter 13 prolongs its magnetism, holdingitsarmature 14 until the relay armature reaches its back stop. At this time the condenser is discharged through the conductors 25 35 and 39*,

the latter including suflicient resistance 40* to prevent the condenser from being short circuited and from producing a spark at the contact 23*. The succeeding break of the a relay armature with its back stop causes the rent to cause it to open this receiving portion of the repeating circuit. A condenser 41* may be connected between the front stop 22* a and the conductor 39 to absorb. the extra current, which would otherwise produce a spark when the circuit of the substation lineis broken at said front contact.

Convenient values for the'capacity of the condensers 38 and 41 are four microfarads and threetenths of a microfarad, respectively. The resistancemay be three hundred ohms.

It will be understood that allthat has been said regarding transmission from substation E to substation F applies equally to the operation of the system in the opposite direction, the transmitting portion of the repeating circuit in the latter case being at the central station B and the receiving portion at the central station A.

A difiiculty arises in the operation of the system which it has been found desirable to remedy, and the means employed for this purpose has another function which is of considerable importance. Suppose the operatorsat the substations E and F were to simultaneously open their keys 28 and 28.

From what has. already been stated, itwill be evident that both transmitters 13, 1? would release their armatures, and this would reverse the current through the windings of the polarized relays 18 18", res ectively. When the armatures of the re ays reach their back stops under the influence of this reversal, they would close the circuits of' the windings. of both transmitters through ground connections 36 and .36; which transmitters, attracting their armatures, would send out reversed currentsand again brin the armatures of the polarized relays to t eir frontstops, this continuin as long as both keys 28 28 are open, an

causing all the relays and sounders of the ystem to chatter until one of the keys is c osed. To overcome this, the transmitters 13" and 13 have a pair'of extra contacts 42 and 42*, respectively, one of each pair being movable with the front contacts 15 and 15", said front and extra contacts being mountedupon springs insulated from one another but adapting the elements for movement-together The contacts 42 and 42" are included in the bridges 19 a and 19 with the windings of, the polarized relays,

and when the transmitters are. energized are closed by the pressure of the armatures 14,

14!. Upon the release; of the armatures, however, the springs separate these extra or bridge contacts, opening the circuits of. the relay windings and rendering them temporarily inoperative. As a consequence of this, each polarized relay responds to current impulses from the distant station only when the home transmitter, and therefore the associated substation line, is closed, and the reactive effect between the ends of the repeating system is impossible. Furthermore, since the winding of each polarized relay is disconnected from the'circuit when the associated transmitter applies reversals of polarity to the line L, the system will not be dependent upon a correct balance between this line and the artificial lines 20, 20 to revent the passage of outgoing currents t rough the relay windings and the maintenance at the relay armatures of the continuity of the sending portion of the repeating system.

Having thus described my invention, 1 claim: 1

1. A telegrapl'i repeating system comprising a circuit having at each of two stations a current reversing transmitter and a polarized relay, and a single-transmission circuit arranged to control the transmitter at one station and being itself directly controlled by the relay at the same station.

2. The combination with telegraph sta-' 3. The combination with two polar duplex telegraph stations connected by a line circuit and each provided with a pole changing transmitter an a polarized relay, of a singlevtransmission line extending to each station,

each of said lines being adapted to control the transmitter at its iome duplex station and being controlled in the contacts of the,

polarized relay at said-station through the transmitter'at the distant duplex station.

4. A telegraph repeating system comprising a transmitting apparatus and a receiving a paratus connected in circuit ateach of a p urality of stations, and means effective upon the operation of the transmitting apparatus for rendering the receiving apparatus at the samestation temporarily inoperative. v 5. A telegraph repeating system CODIPIlS'. ing a current reversing transmitting apparatus and a polarized receiving apparatus connected in circuit at each of two stations, and

.ber, the contact member of the-recciving apmcans controlled in contacts of the transmitting apparatus for opening the circuit of the receiving apparatus at the same stations- 6. A telegrap repeating system comprising a transmitter and a relay connected in circuit at each of two-stations, the transmitter having contacts controlling the relays at botllltll home and distant stations.

7., The combination with two duplex telegraph stations having a line extending between them and each bein connected to an artificial line, of a polarize relay at each station bridged between the connecting line and the artificial line thereat, a transmitter at each station having contacts for controlling the relay at the distant station and for opening and closing the bridge of the relay at the home station, and a single transmission line joined to both the relay and transmitter at each station. 4

8. A telegraph repeating system comprising a transmitting apparatus and areceiving apparatus each provided with a magnetizing winding and with a movable contact memher, the contact member of the receiving apparatus completing a circuit for the winding of the transmitting apparatus at its opposite extremes of movement.

9. A telegraph repeating system comprising a transmitting apparatus and a receiving apparatus each provi ed with a magnetizing winding and with a movable contact memparatus normally completing the energizin circuit for. the transmitting apparatus, and means for supplying current to the winding of the transmitting apparatus during the movement of the contact member of the re cciving ap aratus.

10. A te egraph repeating system comprising a transmitting apparatus and a receiving apparatus each provided with a magnetizing winding and with a movablecontact member, the contact member of the receiving apparatus completing a circuit for the winding of transmitting apparatus at its opposite extremes of movement, and means for supplying current to said winding during the move-' ment of the contact member.

' 11. In a repeating system, the combination with telegraph lines, of a relay provided with a winding and with an armature movable between opposed stops, said winding being connected to one line and one of the stops to another line, a transmitter having a winding in series with the relay armature, and a.

source of current connected to the transmitter windin and being in circuit with both stops of the re ay.

t 12. In a repeating system, the combination with telegraph lines, of a relay provided with a winding and with an armature movable between opposed stops, said winding being connected to one line and one of the stops to another line, a transmitter having a winding in series with the relay armature, a source of current connected. to the transmitter winding and being in circuit with both stops of the relay, and a condenser adapted to be charged from the source of current through the transmitter winding.

13, The combination with a polar bridge duplex telegraph line having the usual polarized relay and electro-magnetic transmitter, of a single-transmission line connected to the front stopof said relay and an artificial line joined to the back stop of said relay, both of the lines being grounded, a grounded battery in circuit with the lever-of the relay and the winding of the transmitter, and a condenser bridged between the back stop and the lever.

14. In a telegraphic system the combination of a I main circuit extending between central terminal stations and operating by current reversals;v branch circuits standing from the said central stations respectively to substations, and operating by current intermittences; a receiving instrument at each central's tation responsive to thecurrent reversals of said main circuit produced at the other central station, and adapted to itself produce corresponding current intermittences in the associated branch circuit; a

transmitting instrument at each central station res onsive to the current in ermittences of the associated branchcircuit and anized to produce corresponding. reverlh in said main circuit; and means controlled by the said transmitting instrument for rendering the receiving instrument at the same station inoperative during each inter -mittence of the associated branch circuit,

substantially as set forth.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses, this 23rd day of WILLIAM E; ATHEARN. Witnesses:

ROBERT Fosrna JANES, SrLvANUs H. Conn.

April 1908. 

